Mapgen: Refactor mapgen creation and management

- Move mapgen creation logic out of EmergeManager and into Mapgen
- Internally represent mapgen type as an enum value, instead of a string
- Remove the need for a MapgenFactory per mapgen

src/emerge.cpp

@@ -34,13 +34,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "log.h"
 #include "map.h"
 #include "mapblock.h"
-#include "mapgen_flat.h"
-#include "mapgen_fractal.h"
-#include "mapgen_v5.h"
-#include "mapgen_v6.h"
-#include "mapgen_v7.h"
-#include "mapgen_valleys.h"
-#include "mapgen_singlenode.h"
 #include "mg_biome.h"
 #include "mg_ore.h"
 #include "mg_decoration.h"
@@ -53,13 +46,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "settings.h"
 #include "voxel.h"
 
-
-struct MapgenDesc {
-	const char *name;
-	MapgenFactory *factory;
-	bool is_user_visible;
-};
-
 class EmergeThread : public Thread {
 public:
 	bool enable_mapgen_debug_info;
@@ -99,20 +85,6 @@ class EmergeThread : public Thread {
 	friend class EmergeManager;
 };
 
-////
-//// Built-in mapgens
-////
-
-MapgenDesc g_reg_mapgens[] = {
-	{"v5",         new MapgenFactoryV5,         true},
-	{"v6",         new MapgenFactoryV6,         true},
-	{"v7",         new MapgenFactoryV7,         true},
-	{"flat",       new MapgenFactoryFlat,       true},
-	{"fractal",    new MapgenFactoryFractal,    true},
-	{"valleys",    new MapgenFactoryValleys,    true},
-	{"singlenode", new MapgenFactorySinglenode, false},
-};
-
 ////
 //// EmergeManager
 ////
@@ -195,24 +167,24 @@ void EmergeManager::initMapgens()
 	if (m_mapgens.size())
 		return;
 
-	MapgenFactory *mgfactory = getMapgenFactory(params.mg_name);
-	if (!mgfactory) {
+	MapgenType mgtype = Mapgen::getMapgenType(params.mg_name);
+	if (mgtype == MAPGEN_INVALID) {
+		const char *default_mapgen_name = Mapgen::getMapgenName(MAPGEN_DEFAULT);
 		errorstream << "EmergeManager: mapgen " << params.mg_name <<
-			" not registered; falling back to " << DEFAULT_MAPGEN << std::endl;
-
-		params.mg_name = DEFAULT_MAPGEN;
+			" not registered; falling back to " <<
+			default_mapgen_name << std::endl;
 
-		mgfactory = getMapgenFactory(params.mg_name);
-		FATAL_ERROR_IF(mgfactory == NULL, "Couldn't use any mapgen!");
+		params.mg_name = default_mapgen_name;
+		mgtype = MAPGEN_DEFAULT;
 	}
 
 	if (!params.sparams) {
-		params.sparams = mgfactory->createMapgenParams();
+		params.sparams = Mapgen::createMapgenParams(mgtype);
 		params.sparams->readParams(g_settings);
 	}
 
 	for (u32 i = 0; i != m_threads.size(); i++) {
-		Mapgen *mg = mgfactory->createMapgen(i, &params, this);
+		Mapgen *mg = Mapgen::createMapgen(mgtype, i, &params, this);
 		m_mapgens.push_back(mg);
 	}
 }
@@ -369,28 +341,6 @@ bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= params.water_level;
 }
 
-
-void EmergeManager::getMapgenNames(
-	std::vector<const char *> *mgnames, bool include_hidden)
-{
-	for (u32 i = 0; i != ARRLEN(g_reg_mapgens); i++) {
-		if (include_hidden || g_reg_mapgens[i].is_user_visible)
-			mgnames->push_back(g_reg_mapgens[i].name);
-	}
-}
-
-
-MapgenFactory *EmergeManager::getMapgenFactory(const std::string &mgname)
-{
-	for (u32 i = 0; i != ARRLEN(g_reg_mapgens); i++) {
-		if (mgname == g_reg_mapgens[i].name)
-			return g_reg_mapgens[i].factory;
-	}
-
-	return NULL;
-}
-
-
 bool EmergeManager::pushBlockEmergeData(
 	v3s16 pos,
 	u16 peer_requested,

src/emerge.h

@@ -140,9 +140,6 @@ class EmergeManager {
 	int getGroundLevelAtPoint(v2s16 p);
 	bool isBlockUnderground(v3s16 blockpos);
 
-	static MapgenFactory *getMapgenFactory(const std::string &mgname);
-	static void getMapgenNames(
-		std::vector<const char *> *mgnames, bool include_hidden);
 	static v3s16 getContainingChunk(v3s16 blockpos, s16 chunksize);
 
 private:

src/mapgen.cpp

@@ -39,6 +39,13 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/numeric.h"
 #include "filesys.h"
 #include "log.h"
+#include "mapgen_flat.h"
+#include "mapgen_fractal.h"
+#include "mapgen_v5.h"
+#include "mapgen_v6.h"
+#include "mapgen_v7.h"
+#include "mapgen_valleys.h"
+#include "mapgen_singlenode.h"
 #include "cavegen.h"
 #include "dungeongen.h"
 
@@ -63,6 +70,28 @@ FlagDesc flagdesc_gennotify[] = {
 	{NULL,               0}
 };
 
+struct MapgenDesc {
+	const char *name;
+	bool is_user_visible;
+};
+
+////
+//// Built-in mapgens
+////
+
+static MapgenDesc g_reg_mapgens[] = {
+	{"v5",         true},
+	{"v6",         true},
+	{"v7",         true},
+	{"flat",       true},
+	{"fractal",    true},
+	{"valleys",    true},
+	{"singlenode", false},
+};
+
+STATIC_ASSERT(
+	ARRLEN(g_reg_mapgens) == MAPGEN_INVALID,
+	registered_mapgens_is_wrong_size);
 
 ////
 //// Mapgen
@@ -121,6 +150,83 @@ Mapgen::~Mapgen()
 }
 
 
+MapgenType Mapgen::getMapgenType(const std::string &mgname)
+{
+	for (size_t i = 0; i != ARRLEN(g_reg_mapgens); i++) {
+		if (mgname == g_reg_mapgens[i].name)
+			return (MapgenType)i;
+	}
+
+	return MAPGEN_INVALID;
+}
+
+
+const char *Mapgen::getMapgenName(MapgenType mgtype)
+{
+	size_t index = (size_t)mgtype;
+	if (index == MAPGEN_INVALID || index >= ARRLEN(g_reg_mapgens))
+		return "invalid";
+
+	return g_reg_mapgens[index].name;
+}
+
+
+Mapgen *Mapgen::createMapgen(MapgenType mgtype, int mgid,
+	MapgenParams *params, EmergeManager *emerge)
+{
+	switch (mgtype) {
+	case MAPGEN_FLAT:
+		return new MapgenFlat(mgid, params, emerge);
+	case MAPGEN_FRACTAL:
+		return new MapgenFractal(mgid, params, emerge);
+	case MAPGEN_SINGLENODE:
+		return new MapgenSinglenode(mgid, params, emerge);
+	case MAPGEN_V5:
+		return new MapgenV5(mgid, params, emerge);
+	case MAPGEN_V6:
+		return new MapgenV6(mgid, params, emerge);
+	case MAPGEN_V7:
+		return new MapgenV7(mgid, params, emerge);
+	case MAPGEN_VALLEYS:
+		return new MapgenValleys(mgid, params, emerge);
+	default:
+		return NULL;
+	}
+}
+
+
+MapgenSpecificParams *Mapgen::createMapgenParams(MapgenType mgtype)
+{
+	switch (mgtype) {
+	case MAPGEN_FLAT:
+		return new MapgenFlatParams;
+	case MAPGEN_FRACTAL:
+		return new MapgenFractalParams;
+	case MAPGEN_SINGLENODE:
+		return new MapgenSinglenodeParams;
+	case MAPGEN_V5:
+		return new MapgenV5Params;
+	case MAPGEN_V6:
+		return new MapgenV6Params;
+	case MAPGEN_V7:
+		return new MapgenV7Params;
+	case MAPGEN_VALLEYS:
+		return new MapgenValleysParams;
+	default:
+		return NULL;
+	}
+}
+
+
+void Mapgen::getMapgenNames(std::vector<const char *> *mgnames, bool include_hidden)
+{
+	for (u32 i = 0; i != ARRLEN(g_reg_mapgens); i++) {
+		if (include_hidden || g_reg_mapgens[i].is_user_visible)
+			mgnames->push_back(g_reg_mapgens[i].name);
+	}
+}
+
+
 u32 Mapgen::getBlockSeed(v3s16 p, s32 seed)
 {
 	return (u32)seed   +
@@ -891,9 +997,9 @@ void MapgenParams::load(const Settings &settings)
 	}
 
 	delete sparams;
-	MapgenFactory *mgfactory = EmergeManager::getMapgenFactory(mg_name);
-	if (mgfactory) {
-		sparams = mgfactory->createMapgenParams();
+	MapgenType mgtype = Mapgen::getMapgenType(mg_name);
+	if (mgtype != MAPGEN_INVALID) {
+		sparams = Mapgen::createMapgenParams(mgtype);
 		sparams->readParams(&settings);
 	}
 }

src/mapgen.h

@@ -26,7 +26,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/string.h"
 #include "util/container.h"
 
-#define DEFAULT_MAPGEN "v6"
+#define MAPGEN_DEFAULT MAPGEN_V6
+#define MAPGEN_DEFAULT_NAME "v6"
 
 /////////////////// Mapgen flags
 #define MG_TREES       0x01
@@ -107,6 +108,17 @@ class GenerateNotifier {
 	std::list<GenNotifyEvent> m_notify_events;
 };
 
+enum MapgenType {
+	MAPGEN_V5,
+	MAPGEN_V6,
+	MAPGEN_V7,
+	MAPGEN_FLAT,
+	MAPGEN_FRACTAL,
+	MAPGEN_VALLEYS,
+	MAPGEN_SINGLENODE,
+	MAPGEN_INVALID,
+};
+
 struct MapgenSpecificParams {
 	virtual void readParams(const Settings *settings) = 0;
 	virtual void writeParams(Settings *settings) const = 0;
@@ -124,7 +136,7 @@ struct MapgenParams {
 	MapgenSpecificParams *sparams;
 
 	MapgenParams() :
-		mg_name(DEFAULT_MAPGEN),
+		mg_name(MAPGEN_DEFAULT_NAME),
 		chunksize(5),
 		seed(0),
 		water_level(1),
@@ -173,6 +185,8 @@ class Mapgen {
 	Mapgen(int mapgenid, MapgenParams *params, EmergeManager *emerge);
 	virtual ~Mapgen();
 
+	virtual MapgenType getType() const { return MAPGEN_INVALID; }
+
 	static u32 getBlockSeed(v3s16 p, s32 seed);
 	static u32 getBlockSeed2(v3s16 p, s32 seed);
 	s16 findGroundLevelFull(v2s16 p2d);
@@ -198,6 +212,14 @@ class Mapgen {
 	// signify this and to cause Server::findSpawnPos() to try another (X, Z).
 	virtual int getSpawnLevelAtPoint(v2s16 p) { return 0; }
 
+	// Mapgen management functions
+	static MapgenType getMapgenType(const std::string &mgname);
+	static const char *getMapgenName(MapgenType mgtype);
+	static Mapgen *createMapgen(MapgenType mgtype, int mgid,
+		MapgenParams *params, EmergeManager *emerge);
+	static MapgenSpecificParams *createMapgenParams(MapgenType mgtype);
+	static void getMapgenNames(std::vector<const char *> *mgnames, bool include_hidden);
+
 private:
 	// isLiquidHorizontallyFlowable() is a helper function for updateLiquid()
 	// that checks whether there are floodable nodes without liquid beneath
@@ -267,11 +289,4 @@ class MapgenBasic : public Mapgen {
 	float cave_width;
 };
 
-struct MapgenFactory {
-	virtual Mapgen *createMapgen(int mgid, MapgenParams *params,
-		EmergeManager *emerge) = 0;
-	virtual MapgenSpecificParams *createMapgenParams() = 0;
-	virtual ~MapgenFactory() {}
-};
-
 #endif

src/mapgen_flat.h

@@ -58,6 +58,8 @@ class MapgenFlat : public MapgenBasic {
 	MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge);
 	~MapgenFlat();
 
+	virtual MapgenType getType() const { return MAPGEN_FLAT; }
+
 	virtual void makeChunk(BlockMakeData *data);
 	int getSpawnLevelAtPoint(v2s16 p);
 	s16 generateTerrain();
@@ -72,16 +74,4 @@ class MapgenFlat : public MapgenBasic {
 	Noise *noise_terrain;
 };
 
-struct MapgenFactoryFlat : public MapgenFactory {
-	Mapgen *createMapgen(int mgid, MapgenParams *params, EmergeManager *emerge)
-	{
-		return new MapgenFlat(mgid, params, emerge);
-	};
-
-	MapgenSpecificParams *createMapgenParams()
-	{
-		return new MapgenFlatParams();
-	};
-};
-
 #endif

src/mapgen_fractal.h

@@ -62,6 +62,8 @@ class MapgenFractal : public MapgenBasic {
 	MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge);
 	~MapgenFractal();
 
+	virtual MapgenType getType() const { return MAPGEN_FRACTAL; }
+
 	virtual void makeChunk(BlockMakeData *data);
 	int getSpawnLevelAtPoint(v2s16 p);
 	bool getFractalAtPoint(s16 x, s16 y, s16 z);
@@ -83,16 +85,4 @@ class MapgenFractal : public MapgenBasic {
 	Noise *noise_seabed;
 };
 
-struct MapgenFactoryFractal : public MapgenFactory {
-	Mapgen *createMapgen(int mgid, MapgenParams *params, EmergeManager *emerge)
-	{
-		return new MapgenFractal(mgid, params, emerge);
-	};
-
-	MapgenSpecificParams *createMapgenParams()
-	{
-		return new MapgenFractalParams();
-	};
-};
-
 #endif